https://medschool.mc.vanderbilt.edu – The human genome encodes hundreds of channels that broker the passage of charged ions across impermeable lipid bilayers1. While energy-requiring pumps labour to build charge and concentration gradients across the membrane, ion channels spend this stored energy, much as a switch releases the electrical energy of a battery. Small conformational changes cause channels to open, allowing over ten million ions to flow per second through each channel. Read more »

http://www.ncbi.nlm.nih.gov – Multiple senses, including hearing, touch and osmotic regulation, require the ability to convert force into an electrical signal: A process called mechanotransduction. Mechanotransduction occurs through specialized proteins that open an ion channel pore in response to a mechanical stimulus. Many of these proteins remain unidentified in vertebrates, but known mechanotransduction channels in lower organisms provide clues into their identity and mechanism. Bacteria, fruit flies and nematodes have all been used to elucidate the molecules necessary for force transduction. Read more »

http://www.ncbi.nlm.nih.gov – Peripheral sensory perception is established through an elaborate network of specialized neurons that mediate the translation of extraorganismal stimuli through the use of a broad array of receptors and downstream effector molecules. Studies of human genetic disorders, as well as mouse and other animal models, have identified some of the key molecules necessary for peripheral innervation and function. Read more »

http://www.sciencedirect.com – In hair cells, mechanotransduction channels are gated by tip links, the extracellular filaments that consist of cadherin 23 (CDH23) and protocadherin 15 (PCDH15) and connect the stereocilia of each hair cell. However, which molecules mediate cadherin function at tip links is not known. Here we show that the PDZ-domain protein harmonin is a component of the upper tip-link density (UTLD), where CDH23 inserts into the stereociliary membrane. Harmonin domains that mediate interactions with CDH23 and F-actin control harmonin localization in stereocilia and are necessary for normal hearing. Read more »